Sabadilla seed insecticide



3,078,211 SABADILLA SEED HNSECTKCHDE John R. Allison, Whittier, Calif.,assignor to Leifingwell Chemicai Company, Whittier, Califi, acorporation of California No Drawing. Continuation of application Ser.No.

29,558, May 17, 1960. This application Apr. 5, 15962,

Ser. No. 185,230

2 Claims. (Cl. 167-4 4) This invention has to do generally with improvedinsecticidal compositions and their methods of manufacture, involving asthe active principle, sabadilla, which in seed form is an alkaloid ormixture of alkaloids known as veratrine, a crystalline substance highlytoxic to plant infestations, particularly the commonly encounteredthrip. As an example of prior art relating to sabadilla insecticidalcompositions, reference may be had to the Allison Patent No. 2,726,188,issued December 6, 1955, on fMethod of Controlling Thrips With SabadillaSeed Composition.

This application is a continuation of my application Serial No. 29,558,filed May 17, 1960, now abandoned, on Insecticide and Its Method ofManufacture.

Sabadilla in aqueous suspension has proven to be the most effectivethrip control agent. The extent of its use, however, has been restrictedby relatively high cost resulting, in part, fromlimitations according topast methods and compositions in making effectively available themaximum active, i.e. alkaloid, content of the seeds. The presentinvention prov-ides for materially increased effectiveness in oil andalkaloid extraction from the seeds, and rendering the extracted activesmost efiiciently useable in ,the final sprayable insecticidalcomposition.

The invention has for one of its major objects to provide an importantimprovement in initial exposure and extraction of oil and alkaloids fromsabadilla seeds, by a grinding procedure which results in the severaladvantages of facilitating and rendering more efficient the physicalaspects of the grinding, and simultaneous exposure in the ground productof the active principles for solvent extraction, and transference to thesame end, of at least some of the oils and alkaloids to a medium whichfunctions in the nature of a grinding aid, to facilitate physicaldisintegration of the seed. Further with respect to the multi-purposeeffects of the grinding aid, the latter is of a nature such as todisplay highly desirable suspension properties in the final sprayablecomposition.

More specifically the invention contemplates initially intergrinding thesabadilla seed with a low bulk density absorptive or adsorptive materialin the category of expanded silicas (such as sold under the trade nameCabasil), expanded pearlite, and vermiculite, all falling in a bulkdensity range of about 2 to pounds per cubic foot. The sabadilla seed isinterground, as in a hammer mill, with the low density siliceousmaterial to a suitable fineness of the mixture, 80% through 200 meshstandard screen, or finer, being preferred. The effect of theintergrinding is to physically expose and release oils and alkaloidsfrom the seed, which are adsorbed onto and within the filler or grindingaid, the adsorptive properties of the latter being such that it has thecapacity for retaining the released oils and alkaloids. By virtue ofthis property, the filler serves as an efficient grinding aid whichtends to prevent or minimize agglomeration of the seed pulp to an oilyor viscous mass not efficiently grindable in itself, which would be thecondition of the seed if ground in the absence of the grinding aid.Using vermiculite, typically and preferably, the latter functions as anadsorptive partitioning agent which tends to keep largly discrete, theseed hulls, and thus promotes and con- 3,078,211 Patented Feb. 19, 1953tinues emcient grinding reduction down to the desired fineness.

The intergr-ound seed and filler may be used as a preliminary product tobe dispersed in a suitable alkaloid solvent such as a freelyWater-miscible ketone or monohydric alcohol, typically acetone,methanol, ethanol, normal isopropanol or tertiary butanol. The primaryfunction of the aqueous solvent is to dissolve the alkaloid in aconcentration most economically effective for thrip killing by sprayapplication of the solution. By at least partial extraction onto or intothe filler of the seed alkaloids, the latter are effectively exposed andrendered available for maximum dissolution. Because of its low bulkdensity, the ground filler tends toward effective dispersion andsuspension in the aqueous solvent, so that it will not settle out as atroublesome residue or interfere with free passage of the solutionthrough spray nozzles.

The invention further contemplates supplementing the aqueous solutionwith any of various additives that may be selected to afford particularbenefits. Thus if some thickening of the solution is desired in order toaid suspension of the powder-alcohol-water system, such thickeners ascarboxy methyl cellulose, alginates and the like, may be dissolved inthe solution in quantities typically up to 3%. It may also beadvantageous for pest control, "to add a suitable deliquescent agentsuch as glycerol, diethylene glycol, or a polyhydric alcohol, to keepthe applied insecticides from becoming dry or exhibiting a tendency toflake off, and also to make the material easier for the thnip toassimilate. Atlas Chemical Company Sorbitol (70%) and molasses have alsobeen used by addition to the final diluted spray composition, aseffective diliquescent agents.

Frequently it may be desirable to add to the solution a suitablesweetening agent such as any of the water soluble sweet-tastingmonosaccharides, e.g. white or brown sugar, lactose, dextrose, fructoseor maltose, or such mixtures as glucose and molasses.

It is desirable that the finished spray composition have a pH betweenabout 4.5 and 8.5, adjustment to which may be had by the addition of asuitable acid, preferably citric acid.

As previously indicated, the method employed in preparing the sprayableproduct, involves first intergrinding sabadilla seed containing around25% oils, with e.g. expanded vermiculite, the latter constituting about20 to 40 weight percent of the mixture, and typically being about 30%.After intergrinding to a fineness of at least about through 200 meshstandard screen, the material then is prepared, as a preliminaryproduct, for introduction to the aqueous solvent.

The interground seed and filler is suspended by agitation in an aqueoussolution of 50 to of the solvent, typically 75% isoprop-anol, theproportion of ground seed and filler to solvent being within the rangeof about %-2 lbs. per gallon of solvent. Uniform dispersion of solidsand solute during the mixing, and thereafter while the composition isbeing sprayed, may be favored by appropriate agitation.

As indicated, thickening of the solution may be accomplished, ifrequired, by the addition of carboxy methyl cellulose or algina-te, andto the solution may be added any desired diliquescent and sweetingagents, usually under five pounds per gallon. It is desirable that thefinal solution be substantially neutral, or at a veriation not greaterthan a pH between about 4.5 and 8.5.

By virtue of the effective extraction of active principles from the seedand ultimately into the solvent, the latter may be given sprayapplication conservatively and at high kill efiiciency.

3 The following is an illustrative final spray compositionmadeintaesordane w th the nve ti n;

Specific Example Isopropanol alcohol gai 60 Intergroundsabad-illa-vermiculite (70% seed),80%

through 200 mesh screen, lbs 100 c l ?T?T"," ?'TT',""' b ?T' 4 Ear-armedsi c oxide di re r l-r. G ycerin; H ,eal.

ma. ins. :z-n-r. a t rgale-:-

from the foregoing it ,will be apparent that invention is distinguished:in its objectives and accomplishments from prior practices or proposalsfor applying a pesticide to a solid carrier whether the latter serves,as such, for dry ,dustingor water slurry application of the mixture. Onesignificant purpose contemplated by the invention in intergrindingsabadilla seed with the low density adsorbent is to condition by bothadsorption and surface exposure on the adsorbent, the insecticidalvalues, and principally the alkaloids, for ultimate maximum extractionfrom the seed and ,d-issolutionin the organic solvent. In this manner,'I am able ,to achieve in excess of 85% extraction into the organicsolvent of the potential alkaloids inth e seed, as distinguished fromextractions ordinarily not in excess of when separately ground andadmixed sabadilla and solid carrier are dispersed in water, e g.according to the disclosure of my prior Patent 2,726,188.

.Inrelation to such prior practices as that ofintergrinding pesticides,eg. ,Aldrin,'with solid carrier (see Handbook of Aldrin, Dieldrin 8rEndrin, Shell Chemical Corporation,-l'95.4) to dilute the pesticide,such expedients do not present'on the carrier sabadillaalkaloids, or theequivalent, which are soluble in organic solvents such as is'opropanol,to the extent of the sabadilla alkaloid sol; ubilities which areresponsible for the high degree of extractability attainable inaccordance with the'invention without excessive solvent useage. Thepresent invention employs the carrier, and the mode of exposing thealkaloids thereon as an intermediary to the final objective of achievingmaximum alkalpid extraction into the solvent, as distinguished from themere use of solids as carriers for a pesticide as in the case of thecited Aldrin useage. And the presence of the adsorbent in the sprayabledispersion is compatible with convenient and efficient spraying byreason of the low bulk density of the adsorbent, and therefore its easyand uniform dispersabiiity in the solution.

As a final observation, the high alkaloid extraction made possible bythe invention, necessitates less than 20% useage of high cost sabadillaseed to achievethe same kill potency attainable by the known waterextraction from separately ground seed.

I claim:

1. The method that includes grinding-together sabadilla seed and lowdensity solid adsorbent acting as a grinding aid to resist agglomerationof the seed hulls and to adsorptively extract on its surface alkaloidsfrom the seed, said adsorbent being of the class consisting of expandedsilicas, pearlite and vermiculite, and having a bulk den,- sity betweenabout 2 and 15 pounds P r cubic foot, and dis e in e re u t und e d arben solvent, said solvent being an aqueous solution of a materialselected from the group consisting of methanol, thano the p op n e y hmno and ac t e- 1 em d o c i 1, i h c .sa ds lvent i a aq eou ut o o opop n lr

1. THE METHOD THAT INCLUDES GRINDING TOGETHER SABADILLA SEED AND LOWDENSITY SOLID ADSORBENT ACTING AS A GRINDING AID TO RESIST AGGLOMERATIONOF THE SEED HULLS AND TO ADSORPTIVELY EXTRACT ON ITS SURFACE ALKALOIDSFROM THE SEED, SAID ADSORBENT BEING OF THE CLASS CONSISTING OF EXPANDEDSILICAS, PEARLITE AND VERMICULITE, AND HAVING A BULK DENSITY BETWEENABOUT 2 AND 15 POUNDS PER CUBIC FOOT, AND DISPERSING THE RESULTINGGROUND SEED AND ADSORBENT IN A SOLVENT, SAID SOLVENT BEING AN AQUEOUSSOLUTION OF A MATERIAL SELECTED FROM THE GROUP CONSISTING OF METHANOL,ETHANOL, THE PROPANOLS, TERTIARY BUTANOL AND ACETONE.